//
// DateTimeParser.h
//
// Library: Foundation
// Package: DateTime
// Module:  DateTimeParser
//
// Definition of the DateTimeParser class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_DateTimeParser_INCLUDED
#define Foundation_DateTimeParser_INCLUDED


#include "Poco/DateTime.h"
#include "Poco/Foundation.h"


namespace Poco
{


class Foundation_API DateTimeParser
/// This class provides a method for parsing dates and times
/// from strings. All parsing methods do their best to
/// parse a meaningful result, even from malformed input
/// strings.
///
/// The returned DateTime will always contain a time in the same
/// timezone as the time in the string. Call DateTime::makeUTC()
/// with the timeZoneDifferential returned by parse() to convert
/// the DateTime to UTC.
///
/// Note: When parsing a time in 12-hour (AM/PM) format, the hour
/// (%h) must be parsed before the AM/PM designator (%a, %A),
/// otherwise the AM/PM designator will be ignored.
///
/// See the DateTimeFormatter class for a list of supported format specifiers.
/// In addition to the format specifiers supported by DateTimeFormatter, an
/// additional specifier is supported: %r will parse a year given by either
/// two or four digits. Years 69-00 are interpreted in the 20th century
/// (1969-2000), years 01-68 in the 21th century (2001-2068).
///
/// Note that in the current implementation all characters other than format specifiers in
/// the format string are ignored/not matched against the date/time string. This may
/// lead to non-error results even with nonsense input strings.
/// This may change in a future version to a more strict behavior.
/// If more strict format validation of date/time strings is required, a regular
/// expression could be used for initial validation, before passing the string
/// to DateTimeParser.
{
public:
    static void parse(const std::string & fmt, const std::string & str, DateTime & dateTime, int & timeZoneDifferential);
    /// Parses a date and time in the given format from the given string.
    /// Throws a SyntaxException if the string cannot be successfully parsed.
    /// Please see DateTimeFormatter::format() for a description of the format string.
    /// Class DateTimeFormat defines format strings for various standard date/time formats.

    static DateTime parse(const std::string & fmt, const std::string & str, int & timeZoneDifferential);
    /// Parses a date and time in the given format from the given string.
    /// Throws a SyntaxException if the string cannot be successfully parsed.
    /// Please see DateTimeFormatter::format() for a description of the format string.
    /// Class DateTimeFormat defines format strings for various standard date/time formats.

    static bool tryParse(const std::string & fmt, const std::string & str, DateTime & dateTime, int & timeZoneDifferential);
    /// Parses a date and time in the given format from the given string.
    /// Returns true if the string has been successfully parsed, false otherwise.
    /// Please see DateTimeFormatter::format() for a description of the format string.
    /// Class DateTimeFormat defines format strings for various standard date/time formats.

    static void parse(const std::string & str, DateTime & dateTime, int & timeZoneDifferential);
    /// Parses a date and time from the given dateTime string. Before parsing, the method
    /// examines the dateTime string for a known date/time format.
    /// Throws a SyntaxException if the string cannot be successfully parsed.
    /// Please see DateTimeFormatter::format() for a description of the format string.
    /// Class DateTimeFormat defines format strings for various standard date/time formats.

    static DateTime parse(const std::string & str, int & timeZoneDifferential);
    /// Parses a date and time from the given dateTime string. Before parsing, the method
    /// examines the dateTime string for a known date/time format.
    /// Please see DateTimeFormatter::format() for a description of the format string.
    /// Class DateTimeFormat defines format strings for various standard date/time formats.

    static bool tryParse(const std::string & str, DateTime & dateTime, int & timeZoneDifferential);
    /// Parses a date and time from the given dateTime string. Before parsing, the method
    /// examines the dateTime string for a known date/time format.
    /// Please see DateTimeFormatter::format() for a description of the format string.
    /// Class DateTimeFormat defines format strings for various standard date/time formats.

    static int parseMonth(std::string::const_iterator & it, const std::string::const_iterator & end);
    /// Tries to interpret the given range as a month name. The range must be at least
    /// three characters long.
    /// Returns the month number (1 .. 12) if the month name is valid. Otherwise throws
    /// a SyntaxException.

    static int parseDayOfWeek(std::string::const_iterator & it, const std::string::const_iterator & end);
    /// Tries to interpret the given range as a weekday name. The range must be at least
    /// three characters long.
    /// Returns the weekday number (0 .. 6, where 0 = Synday, 1 = Monday, etc.) if the
    /// weekday name is valid. Otherwise throws a SyntaxException.

protected:
    static int parseTZD(std::string::const_iterator & it, const std::string::const_iterator & end);
    static int parseAMPM(std::string::const_iterator & it, const std::string::const_iterator & end, int hour);
};


} // namespace Poco


#endif // Foundation_DateTimeParser_INCLUDED
